The completion times for a job task range from 10.6 minutes to 18.6 minutes and are thought to be uniformly distributed. what is the probability that it will require between 13.8 and 16.8 minutes to perform the task?

Recall that the area under a probability curve is always 1.0. Here we have a probability distribution from 10.6 to 18.6 minutes, of length 10 minutes, so the height of the probability "curve" is 1.0 / 10, or 0.1.

To answer this question, find the area under the probability "curve" between 13.8 and 16.8 minutes. The difference between 13.8 and 16.8 is 3 units, so the desired probability is 3 (0.1), or 0.30.